How much heat is transferred in 1 hour by the process conduction through a concrete wall 2 m high, 3.65 m long and 0.2 m thick if one side of the wall is held at 20 °C and the other side at 5.0 °C? [Take the thermal conductivity of concrete as 1.3×10-6 Wm-1°C-1].
To calculate the amount of heat transferred through conduction, we can use the formula:
Q = (k * A * ΔT) / d
Where:
Q = Heat transferred (in joules)
k = Thermal conductivity of concrete (in W/m°C)
A = Surface area of the wall (in m²)
ΔT = Temperature difference across the wall (in °C)
d = Thickness of the wall (in m)
First, let's calculate the surface area of the wall:
A = height * length
A = 2 m * 3.65 m
A = 7.3 m²
Next, let's calculate the temperature difference:
ΔT = Thot - Tcold
ΔT = 20 °C - 5.0 °C
ΔT = 15.0 °C
Now, substitute the values into the formula to find the heat transferred (Q):
Q = (1.3×10^-6 W/m°C * 7.3 m² * 15.0 °C) / 0.2 m
Simplifying the expression:
Q = (1.3×10^-6 * 7.3 * 15) / 0.2
Q ≈ 1313 Joules
Therefore, the amount of heat transferred through conduction in 1 hour is approximately 1313 joules.